Abstract: A cephem derivative represented by the general formula ##STR1## wherein R.sup.1 represents hydrogen or methyl, R.sup.2 represents carboxyl or esterified carboxyl, and n represents 0 or 1, or a pharmaceutically acceptable salt thereof; intermediates for the cephem derivative or salt thereof; processes for producing these compounds; and a pharmaceutical composition and method for preventing or treating bacterial infectious diseases, wherein the cephem derivative or the salt thereof is used.

Abstract: A cephem compound represent by the general formula ##STR1## wherein, R.sup.1 represents hydrogen or lower alkyl, R.sup.2 and R.sup.3 are the same or different and each represents hydrogen or lower alkyl, R.sup.4 represents carboxyl or esterified carboxyl, and n represents 0 or 1, a salt of the cephem compound, and a process for producing the cephem compound or a salt thereof. Compounds of the above formula and salts thereof are valuable as antibacterial agents and are especially useful as oral drugs in the prevention or treatment of bacterial infectious diseases.

Abstract: An improved process for producing a peptide and a cephalosporin which comprises treating a phosphoramide derivative of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are each an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, and A.sub.1 is a peptide residue or a cephalosporin residue, with a phosphorus acid to produce a peptide or a cephalosporin of the formula A.sub.1 --NH.sub.2 wherein A.sub.1 is as hereinbefore defined.

Abstract: Novel penicillin derivatives of the formula (I) ##STR1## wherein R.sup.1 represents a lower alkyl group and R.sup.2 represents an ester protective group, as hereinafter defined and 7-amino-3-desacetoxycephalosporanic acid derivatives of the formula (II) ##STR2## wherein R.sup.1 represents a lower alkyl group and R.sup.2 represents an ester protective group, which are useful as precursors for the production of cephalosporin derivatives, and an improved process for producing cephalosporin derivatives of the formula (II) above and the formula (III) ##STR3## wherein R.sup.2 is an ester protective group, are disclosed.

Abstract: A process for producing a compound of the formula (I) ##SPC1##wherein R.sub.2 is a hydrogen atom or an ester protective group, which is useful as a precursor for the production of cephalosporin derivatives, comprising reacting a phosphoramide derivative of cephalosporin of the formula (II) ##SPC2##wherein R.sub.1 is a lower alkyl group and R.sub.2 is as defined above, with a phosphorus acid. A further embodiment includes preparing the phosphoramide derivative of cephalosporin of the formula (II) by reactng a compound of the formula (III) ##SPC3##wherein R.sub.1 and R.sub.2 are as defined above, with an acid compound.